mineral

Tumbled amethyst

Quartz, purple variety (SiO₂), colored mainly by iron-related defects and irradiation

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, translucent purple color, conchoidal fracture, and no cleavage; quartz has a trigonal crystal structure. The specimen appears polished/tumbled, with pale lavender zoning and internal fractures.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst forms when iron-bearing quartz develops in volcanic cavities, hydrothermal veins, or geodes; coloration occurs during later irradiation and heating. Most commercial material formed in Phanerozoic volcanic rocks, commonly in Brazil, Uruguay, Zambia, and Bolivia.

Uses & applications

Used as a gemstone, ornamental stone, cabochon, beads, and collectible mineral; it is also popular in polished décor. It is not generally used as a structural construction stone.

Geological facts

Identify it by its purple quartz color, glassy luster, hardness, and lack of cleavage; it should scratch ordinary glass but not be scratched by a steel knife. Common localities include Rio Grande do Sul and Artigas, Uruguay, where large geodes occur.

Field identification & locations

Natural amethyst commonly shows color zoning, quartz crystal faces, or drusy surfaces; uniform vivid purple may indicate enhancement or dye. Avoid prolonged strong sunlight, which can fade some specimens.